class_docstr: A file-ish object that can have new data loaded into it.
  
  You can also push and pop line-matching predicates onto a stack.  When the
  current predicate matches the current line, a false EOF response
  (i.e. empty string) is returned instead.  This lets the parser adhere to a
  simple abstraction -- it parses until EOF closes the current message.
code: def __init__(self):
      # Text stream of the last partial line pushed into this object.
      # See issue 22233 for why this is a text stream and not a list.
      self._partial = StringIO(newline="")
      # A deque of full, pushed lines
      self._lines = deque()
      # The stack of false-EOF checking predicates.
      self._eofstack = []
      # A flag indicating whether the file has been closed or not.
      self._closed = False
  
imports: import re
  from email import errors
  from email._policybase import compat32
  from collections import deque
  from io import StringIO
label_desc: Use image node_id 1 to create a new BufferedSubFile object from inherited base classes: object with example: obj = BufferedSubFile()